GoPro sinks 8%

In an article last weekend, Barron's magazine wrote that the company's stock could fall to $25 a share. That's a 29% decline from Friday's closing price of $35.15.

The stock is already down 44% year-to-date.

Alexander Eule at Barron's wrote that the big downside for GoPro was competition. Eule calls the company's point-of-view cameras a "one-product wonder" and compares them to BlackBerry smartphones that were once all the rage.

The article said Apple was a looming threat; when it emerged in January that Apple had obtained a patent for a camera that could compete with GoPro's cameras, shares fell 12%.

Also, the Chinese manufacturer Xiaomi announced a 16-megapixel camera that was similar to and much cheaper than GoPro cameras.